1 /*
   2  * Copyright (c) 2009, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /**
  27  * IOUtils: A collection of IO-related public static methods.
  28  */
  29 
  30 package sun.misc;
  31 
  32 import java.io.EOFException;
  33 import java.io.IOException;
  34 import java.io.InputStream;
  35 import java.util.Arrays;
  36 
  37 public class IOUtils {
  38 
  39     /**
  40      * Read up to <code>length</code> of bytes from <code>in</code>
  41      * until EOF is detected.
  42      * @param is input stream, must not be null
  43      * @param length number of bytes to read, -1 or Integer.MAX_VALUE means
  44      *        read as much as possible
  45      * @param readAll if true, an EOFException will be thrown if not enough
  46      *        bytes are read. Ignored when length is -1 or Integer.MAX_VALUE
  47      * @return bytes read
  48      * @throws IOException Any IO error or a premature EOF is detected
  49      */
  50     public static byte[] readFully(InputStream is, int length, boolean readAll)
  51             throws IOException {
  52         byte[] output = {};
  53         if (length == -1) length = Integer.MAX_VALUE;
  54         int pos = 0;
  55         while (pos < length) {
  56             int bytesToRead;
  57             if (pos >= output.length) { // Only expand when there's no room
  58                 bytesToRead = Math.min(length - pos, output.length + 1024);
  59                 if (output.length < pos + bytesToRead) {
  60                     output = Arrays.copyOf(output, pos + bytesToRead);
  61                 }
  62             } else {
  63                 bytesToRead = output.length - pos;
  64             }
  65             int cc = is.read(output, pos, bytesToRead);
  66             if (cc < 0) {
  67                 if (readAll && length != Integer.MAX_VALUE) {
  68                     throw new EOFException("Detect premature EOF");
  69                 } else {
  70                     if (output.length != pos) {
  71                         output = Arrays.copyOf(output, pos);
  72                     }
  73                     break;
  74                 }
  75             }
  76             pos += cc;
  77         }
  78         return output;
  79     }
  80 }